GB2084690A

GB2084690A - Inducing lift on a stationary wing

Info

Publication number: GB2084690A
Application number: GB8031223A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-09-26
Filing date: 1980-09-26
Publication date: 1982-04-15

Abstract

The invention claims to give conventional fixed wing aircraft the ability to take off vertically and hover using a propulsive thrust which is considerably less than the aircraft weight, the wing having leading (7, 9) and trailing (6, 10) edge flaps, wing fins (5) on upper and lower surfaces at approximately mid semi-span, continuous propulsive flaps (9, 10) at the wing inboard leading edge and the outboard trailing edge, and intake slots (11, 12) at the wing inboard leading edge and the outboard trailing edge. For VTOL, the leading and trailing edge flaps are lowered, a rearward airflow over the wing inboard of fins (5) being induced by leading edge blowing (1), and a forward airflow over the wing outboard of fins (5) by forward blowing (3) at the trailing edge, the required air being drawn into intakes (11, 12). For cruise, the flaps are at zero deflection and the trailing edge blowing is directed rearwardly. Differential blowing can be used for control. <IMAGE>

Description

SPECIFICATION Vertical take-off aircraft using fixed wings and horizontal propulsion units having appreciable less thrust than the aircraft weight I, Sidney Walmsley of 3, Highbury Road West, St Annes, Lancashire, England, a citizen of England do hereby declare this invention to be described in the following statement: Aircraft have previously been designed using a wing, a propulsive device and an undercarriage. The aircraft accelerates horizontally along the ground or runway until a speed is reached when the wing generates sufficient lift to overcome the weight, and the aircraft becomes airborne. These winged aircraft require thrusts less than their weights.

Large high speed aircraft require such long runways that airports are now situated at large distances from the city centers. Aircraft have therefore been designed to take off vertically. Such designs require to generate propulsive thrusts equal to or greater than their weight. Successful designs have included helicopters, jump sets, fan in wing, rotating wing with engine attached, rotating engines with fixed wings, rotating aircraft (tail sitting aircraft) special lift engines (in addition to the forward propulsion engines) and have used rotors, propellers and pure jets (from turbines, fans and rockets) as the propulsive devices. Helicopters have been made more efficient during cruising flight by stopping a four bladed rotor and allowing two of the blades to act as conventional fixed wings.

Other aircraft have been designed to take off in a short distance with the thrust less than the weight, using a fixed wing plus additional devices such as large wings, large flaps, blown flaps and jet flaps.

The wing has been made more efficient by the use of nose flaps.

The use of a thrust less than the weight leads to light engine weight and low fuel consumption which in turn leads to increased range and low aircraft operating costs.

The invention to be described allows a conventional fixed wing aircraft to develop a lift equal to or greater than the weight at zero aircraft forward speed, using horizontal propulsive units with less thrust than the aircraft weight.

Figure 1 gives a plan view of the aircraft.

Figure 2 gives a side view of the aircraft at take-off.

Figure 3 gives a cross sectional view of the inboard leading edge at take off, hover and cruise.

Figure 4 gives a cross sectional view of the outboard trailing edge at take off.

Figure 5 gives a cross sectional view of the outboard leading edge at take off and cruise.

Figure 6gives a cross sectional view of the outboard trailing edge at cruise.

Figure 7gives a cross sectional view of the inboard trailing edge at take off, hover and cruise.

Lift from fixed wings at zero forward aircraft speed is achieved by using a thrust in the forward direction from the inboard propulsion units and a thrust in the aft direction from the outboard propulsion units, or vice versa. The propulsion units produce a high speed air flow over the wing which generates lift.

The forward thrust over the inboard wing is balanced by the aft thrust over the outboard wing so there is zero net thrust available to move the aircraft forward so that it has vertical take-off and hovering capability.

The air from the propulsion units is designed to entrain the maximum amount of free stream air over the wing and this is given the maximum amount of downward deflection by the flaps. The maximum air entrainment over the wing is accomplished by using propulsion air applied continuously along the full wing span. If conventional propellers are used, this implies many small diameter propellers. The efficiency of air entrainment, however, is increased by using engines to produce pressurised air (1) which is discharged aft from a thin slot (2) at the leading edge of the wing over both the upper and lower wing surfaces of the inboard wing and air (3) discharged forward from a thin slot (4) at the trailing edge of the wing over both the upper and lower wing surfaces of the outboard wing.

The aft moving air is designed to have the minimum possible interaction with the forward moving air and this is accompanied by using a thin chordwise airfoil structure (5) between the two airflows on both the upper and lower wing surfaces.

This airfoil can also act as a control fin.

The propulsive and entrained air is given the maximum downwards deflection by the use of a large flap (9) at a large downward deflection angle at the wing trailing edge over the inboard region and a large flap (10) set at a large downward deflection angle at the wing leading edge overthe outboard region.

During the cruise the flaps are given zero deflection in order to obtain the maximum possible lift to drag ratio and the wing takes up an angle of attack relative to the free stream air to generate a lift equal to the weight.

Athrust is required during the cruise in the forward direction to overcome the drag in the aft direction and hence the direction of thrust over the outboard wing has to be reversed. This is accomplished by reversing the pitch angle of the outboard propeller blades, if they are used, or directing the flow of air (8) in the aft direction from the outboard slot at the trailing edge for jet aircraft.

During take off and hover the air from the wing flaps is given a large downwards motion but the air into the propulsion units should be induced to have a large upwards motion so as to produce the maximum possible lift in the upwards direction on the wing. This is achieved by using large downward deflected 'nose' flaps (6) at the leading edge over the inboard wing and nose flaps (7) at the trailing edge over the outboard wing.

During the cruise these nose flaps as well as the main flaps will have zero deflection.

The air to the engines is through an intake (11) below the leading edge of the inboard nose flaps at the leading part of the wing for the take off, hover and cruise phases of the flight, and through an intake (12) below the trailing edge of the outboard nose flap at the trailing part of the wing for the take off and hover phases of the flight but not for the cruise phase of the flight. Again the amount of air induced to flow over the wing by entrainment is increased and the wing efficiency thereby increased by using an intake in the form of a slot along the whole length of the inboard nose flap and a slot along the whole length of the outboard nose flap for take off and hover and a slot along the whole length of the inboard nose flap only for the cruise phase of the flight.

Because the flow of air is always aft for both hover and cruise for the inboard wing then the airfoil over the inboard wing has a conventional shape with a rounded leading edge and a sharp trailing edge for subsonic aircraft. The air changes direction over the outboard wing from hover to cruise so that the leading and trailing edges have a compromise shape, i.e. a small radius. Air flows to the leading edge thrust slot over the inboard wing through a duct (13) and air flows to the trailing edge thrust slot over the outboard wing through a duct (14). The aircraft can accelerate horizontally by applying more forward thrust from the inboard slots then aft thrust from the outboard slots.

During take off and hover, aircraft control in pitch can be achieved by using a different flap angle at the leading edge to the flap angle at the trailing edge; aircraft control in roll can be achieved by using different flap angles on the port wing to the starboard wing; and aircraft control in yaw can be achieved by increasing the airflow in the aft direction relative to the forward direction for one wing and vice versa for the other wing.

During the cruise, aircraft control in pitch and yaw can be obtained from the conventional elevators and rudder; aircraft control in roll can be obtained from differential actuation of the port and starboard inboard trailing edge flaps. Alternatively if there is no tail unit, aircraft control in pitch can be obtained by deflecting the port and starboard inboard trailing edge flaps in the same direction; aircraft control in yaw can be obtained by deflecting the rudder which is supported from the trailing edge of the wing fins; and aircraft control in roll can be obtained from differential actuation of the port and starboard inboard trailing edge flaps.

The propulsion jet velocity must always exceed the aircraft cruise speed and the propulsion slot width and intake slot width can be determined from the airflow required at take off, hover and cruise.

The invention has great military significance as well as civil aircraft significance. Military aircraft which use the invention will now have long range but can operate from places without runways.

Claims

CLAIM

It is claimed that the invention

1. gives a conventional fixed wing aircraft the ability to take off vertically and hover using a propulsion thrust which is considerably less than the aircraft weight using leading and trailing edge flaps, wing fins on upper and lower surfaces at approximately mid semi-span, continuous propulsive slots at the wing inboard leading edge and the outboard trailing edge, and intake slots at the wing inboard leading edge and the outboard trailping edge; and yet have a performance in cruise equal to conventional fixed wing aircraft with low thrust to weight ratios by reversing the direction of air flow over the outboard wing by use of the trailing edge slot control.

New claims or amendments to claims filed on 22 Dec 1980 Superseded claims 1 New or amended claims:

1. The invention gives a conventional fixed wing aircraft the ability to take off vertically and hover using a propulsion thrust which is considerably less than the aircraft weight using leading and trailing edge flaps, wing fins on upper and lower surfaces at approximately mid semi-span, continuous propul sive slots at the wing inboard leading edge and the outboard trailing edge upper and lower surfaces, and intake slots at the wing inboard leading edge and the outboard trailing edge; and yet have a performance in cruise equal to conventional fixed wing aircraft with low thrust to weight ratios by reversing the direction of air flow over the outboard wing by use of the trailing edge slot control.